A camera-enabled device (e.g., a digital camera or a camera-enabled phone) includes a camera module comprising a matrix of optical sensors that converts spatial optical information, e.g., luminosity and color values sensed by the optical sensors, into a matrix or an array of digital information. The camera module is the image-capturing component of the camera-enabled device. The camera module may be integrated with control electronics and an output interface to other logic component(s) of the camera-enabled device. The camera module may include an integrated lens system or be compatible with an external lens system. A typical manufacturer of the camera-enabled device may purchase a pre-assembled camera module and/or a lens system from a separate manufacturer.
The camera-enabled device can further include an image processor that transforms the digital information into a digital image. The appearance of digital images produced from this process may depend on the consistency amongst the optical sensors and other optical elements (e.g., the lens system). However, the manufacturing process of the optical sensors and other optical elements oftentimes produces hardware and/or sensitivity differences that may translate to inconsistencies amongst the optical sensors and the optical elements. For example, if a first set of optical sensors is more sensitive to white light than a second set of optical sensors, a digital image of a blanket white canvas produced from these optical sensors may appear rippled or distorted.
Manufacturers of “high-end” camera modules test the optical sensors in their labs and produce a set of calibration parameters corresponding to the matrix of optical sensors. The sensor manufacturers can then store the calibration parameters in a memory module of the camera module. A manufacturer of the camera-enabled device can purchase the camera module and install it in the camera-enabled device. The image processor can then access the memory module of the camera module for the calibration parameters.
During operation of the camera-enabled device, the image processor can read the outputs of the optical sensors from the camera module and adjust the outputs according to the calibration parameters. The calibration parameters may be spatially based on the locations of the optical sensors. These high-end cameras would require additional memory in the camera module to store the calibration parameters.
A digital camera module can be an expensive part of a camera-enabled phone. The testing process to define the calibration parameters is expensive, and the additional memory for the calibration parameters is also expensive. However, if the manufacturers of the camera module forego the testing process and the additional memory, the images produced from its camera module may then be inconsistent or distorted due to lack of calibration. Thus, images captured by these “low-end” camera modules can be quite inferior as compared to high-end camera modules.
The figures depict various embodiments of this disclosure for purposes of illustration only. One skilled in the art will readily recognize that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the invention described herein.